Shopp storage add-ons are not WordPress plugins. They cannot be installed through the WordPress Plugins interface within the WordPress admin. Storage add-ons for Shopp need to be added to the storage subfolder within the Shopp plugin folder.

Shopp shipping add-ons are not WordPress plugins. They cannot be installed through the WordPress Plugins interface within the WordPress admin. Shipping add-ons for Shopp need to be added to the shipping subfolder within the Shopp plugin folder.

Shopp gateway add-ons are not WordPress plugins. They cannot be installed through the WordPress Plugins interface within the WordPress admin. Gateway add-ons for Shopp need to be added to the gateway subfolder within the Shopp plugin folder.